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About Multiple Myeloma
Overview
If you have been diagnosed with multiple myeloma or are worried about it, you likely
have a lot of questions. Learning some basics is a good place to start.
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What Is Multiple Myeloma?
Research and Statistics
See the latest estimates for new cases of multiple myeloma and deaths in the US and
what research is currently being done.
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What Are the Key Statistics About Multiple Myeloma?
What’s New in Multiple Myeloma Research and Treatment?
What Is Multiple Myeloma?
Cancer starts when cells in the body begin to grow out of control. Cells in nearly any
part of the body can become cancer, and can spread to other areas of the body. To
learn more about how cancers start and spread, see What Is Cancer?
Multiple myeloma is a cancer formed by malignant plasma cells. Normal plasma cells
are found in the bone marrow and are an important part of the immune system.
The immune system is made up of several types of cells that work together to fight
infections and other diseases. Lymphocytes (lymph cells) are the main cell type of the
immune system. The major types of lymphocytes are T cells and B cells.
When B cells respond to an infection, they mature and change into plasma cells.
Plasma cells make the antibodies (also called immunoglobulins) that help the body
attack and kill germs. Lymphocytes are in many areas of the body, such as lymph
nodes, the bone marrow, the intestines, and the bloodstream. Plasma cells, however,
are mainly found in the bone marrow. Bone marrow is the soft tissue inside some hollow
bones. In addition to plasma cells, normal bone marrow has cells that make the different
normal blood cells.
When plasma cells become cancerous and grow out of control, they can produce a
tumor called a plasmacytoma. These tumors generally develop in a bone, but they are
also rarely found in other tissues. If someone has only a single plasma cell tumor, the
disease is called an isolated (or solitary) plasmacytoma. If someone has more than one
plasmacytoma, they have multiple myeloma.
Multiple myeloma is characterized by several features, including:
Low blood counts
In multiple myeloma, the overgrowth of plasma cells in the bone marrow can crowd out
normal blood-forming cells, leading to low blood counts. This can cause anemia – a
shortage of red blood cells. People with anemia become pale, weak, and fatigued.
Multiple myeloma can also cause the level of platelets in the blood to become low
(called thrombocytopenia). This can lead to increased bleeding and bruising. Another
condition that can develop is leukopenia – a shortage of normal white blood cells. This
can lead to problems fighting infections.
Bone and calcium problems
Myeloma cells also interfere with cells that help keep the bones strong. Bones are
constantly being remade to keep them strong. Two major kinds of bone cells normally
work together to keep bones healthy and strong. The cells that lay down new bone are
called osteoblasts. The cells that break down old bone are called osteoclasts. Myeloma
cells make a substance that tells the osteoclasts to speed up dissolving the bone. Since
the osteoblasts do not get a signal to put down new bone, old bone is broken down
without new bone to replace it. This makes the bones weak and they break easily.
Fractured bones are a major problem in people with myeloma. This increase in bone
break-down can also raise calcium levels in the blood. (Problems caused by high
calcium levels are discussed in How Is Multiple Myeloma Diagnosed?)
Infections
Abnormal plasma cells do not protect the body from infections. As mentioned before,
normal plasma cells produce antibodies that attack germs. For example, if you
developed pneumonia, normal plasma cells would produce antibodies aimed at the
specific bacteria that were causing the illness. These antibodies help the body attack
and kill the bacteria. In multiple myeloma, the myeloma cells crowd out the normal
plasma cells, so that antibodies to fight the infection can’t be made. The antibody made
by the myeloma cells does not help fight infections. That’s because the myeloma cells
are just many copies of the same plasma cell – all making copies of the same exact (or
monoclonal) antibody.
Kidney problems
The antibody made by myeloma cells can harm the kidneys. This can lead to kidney
damage and even kidney failure.
Monoclonal gammopathy
Having many copies of the same antibody is known as a monoclonal gammopathy. This
condition can be found with a blood test. Although people with multiple myeloma have a
monoclonal gammopathy, not everyone with monoclonal gammopathy has multiple
myeloma. It can also occur in other diseases, such as Waldenstrom macroglobulinemia
and some lymphomas. It can also occur in a disorder known as monoclonal
gammopathy of undetermined significance (MGUS), whichdoes not cause problems like
multiple myeloma does. However, some people with MGUS will eventually go on to
develop multiple myeloma or other diseases.
Light chain amyloidosis
Antibodies are made up of protein chains joined together – 2 short light chains and 2
longer heavy chains. In light chain amyloidosis, abnormal plasma cells make too many
light chains. These light chains can deposit in tissues, where they build up. This
accumulation of light chains can lead to an abnormal protein in tissues known as
amyloid. The buildup of amyloid in certain organs can lead them to enlarge and not
work well. For example, when amyloid builds up in the heart, it can cause an irregular
heart beat and cause the heart to enlarge and get weaker. A weak heart can lead to a
condition called congestive heart failure, with symptoms like shortness of breath and
swelling in the legs. Amyloid in the kidneys can cause them to work poorly. This may
not cause symptoms early on, but the poor kidney function may be found on blood tests.
If it gets worse, amyloid in the kidney can lead to kidney failure. See Signs and
Symptoms of Multiple Myeloma for more information about the signs and symptoms of
light chain amyloidosis.
Other names for light chain amyloidosis include AL and primary amyloidosis. This is
sometimes considered a separate disease from multiple myeloma, but because
treatment is often similar to that of myeloma, we will discuss it in this document.
Light chain amyloidosis is only one of the diseases where amyloid builds ups and
causes problems. Amyloidosis can also be caused by a genetic (hereditary) disease
called familial amyloidosis. Long-standing (chronic) infection and/or inflammation can
also cause amyloidosis. This is known as secondary or AA amyloidosis. This document
does not talk about these other kinds of amyloidosis.
Monoclonal gammopathy of undetermined
significance
In monoclonal gammopathy of undetermined significance (MGUS), abnormal plasma
cells produce many copies of the same antibody (a monoclonal antibody protein).
However, these plasma cells do not form an actual tumor or mass and do not cause any
of the other problems seen in multiple myeloma. MGUS usually does not affect a
person’s health. In particular, it doesn’t cause weak bones, high calcium levels, kidney
problems, or low blood counts. It’s most often found when a routine blood test finds a
high level of protein in the blood and further testing shows the protein is a monoclonal
antibody. In MGUS, the number of plasma cells may be increased, but they still make
up less than 10% of the cells in the bone marrow.
Some people with MGUS will eventually develop multiple myeloma, lymphoma, or
amyloidosis. Each year, about 1% of people with MGUS develops one of these
diseases. The risk is higher in people whose protein levels are particularly high. Patients
with MGUS don’t need treatment, but they are watched closely to see if they get a
disease that does need to be treated, such as multiple myeloma.
Recently, scientists have studied the genes of the plasma cells in patients with MGUS.
They found that the genetic make-up of these plasma cells resembles myeloma plasma
cells more than it resembles that of normal plasma cells. This suggests that these cells
are truly malignant, not just slow growing. Because people with MGUS are generally
elderly, they may not live long enough for it to transform into myeloma.
Solitary plasmacytomas
This is another type of abnormal plasma cell growth. Rather than many tumors in
different locations as in multiple myeloma, there is only one tumor, hence the name
solitary plasmacytoma.
Most often, a solitary plasmacytoma develops in a bone, where it may be called an
isolated plasmacytoma of bone. When a plasmacytoma starts in other tissues (such as
the lungs or other organs), it is called an extramedullary plasmacytoma. Solitary
plasmacytomas are most often treated with radiation therapy. Sometimes surgery may
be used for a single extramedullary plasmacytoma. As long as no other plasmacytomas
are found later on, the patient’s outlook is usually excellent. However, since many
people with a solitary plasmacytoma will develop multiple myeloma, these people are
watched closely for signs of this disease.
References
See all references for Multiple Myeloma
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Last Medical Review: May 22, 2014 Last Revised: January 19, 2016
American Cancer Society medical information is copyrighted material. For reprint
requests, please see our Content Usage Policy.
What Are the Key Statistics About
Multiple Myeloma?
Multiple myeloma is a relatively uncommon cancer. In the United States, the lifetime risk
of getting multiple myeloma is 1 in 143 (0.7%).
The American Cancer Society’s estimates for multiple myeloma in the United States for
2017 are:
About 30,280 new cases will be diagnosed (17,490 in men and 12,790 in women).
About 12,590 deaths are expected to occur (6,660 in men and 5,930 in women).
Visit the American Cancer Society’s Cancer Statistics Center for more key statistics.
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References
See all references for Multiple Myeloma
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Last Medical Review: May 22, 2014 Last Revised: January 6, 2017
American Cancer Society medical information is copyrighted material. For reprint
requests, please see our Content Usage Policy.
What’s New in Multiple Myeloma
Research and Treatment?
Important research into multiple myeloma is being done in many university hospitals,
medical centers, and other institutions around the world. Each year, scientists find out
more about what causes the disease and how to improve treatment. Many new drugs
are being tested.
Researchers have found that bone marrow-support tissues and bone cells produce
growth factors that increase the growth of myeloma cells. In turn, the myeloma cells
produce substances that cause bone cells to undergo changes that weaken the bones.
These discoveries are helping the researchers develop new drugs to block these growth
factors, slow down the cancer, and reduce bone destruction. For example, bone marrow
support (stromal) cells produce interleukin-6 (IL-6). Because IL-6 is a strong growth
factor for multiple myeloma cells and eventually destroys bone, some current research
efforts are focused on developing ways to block IL-6 function.
A form of arsenic, arsenic trioxide, is used to treat a certain kind of leukemia, and is also
being tested to treat myeloma.
Drugs that act differently than the ones in use are being studied. For example, a drug
called panobinostat is a histone deacetylase (HDAC) inhibitor, which means it affects
the proteins in chromosomes. It has shown promising results when used in combination
with bortezomib (Velcade) and dexamethasone, and it is now approved for use along
with these drugs.
A test called gene expression profiling has been studied in recent years in multiple
myeloma. This test looks to see what genes are active in cancer cells, and may be able
to tell if and when a patient with multiple myeloma will need to have chemotherapy.
Much more work lies ahead though, before this test can be used routinely.
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References
See all references for Multiple Myeloma
Last Medical Review: May 22, 2014 Last Revised: January 19, 2016
American Cancer Society medical information is copyrighted material. For reprint
requests, please see our Content Usage Policy.
2016 Copyright American Cancer Society